The basic method and system for transporting natural gas under high pressure and at ambient temperatures in movable pressure vessels is described in U.S. Pat. No. 4,139,019, directed to an invention which made possible the recovery of natural gas from isolated or shut-in gas wells where the normal procedure of constructing a pipeline to the well was not feasible or not possible. The system described in that patent includes at least one pressure vessel mounted for transport, and designed to carry natural gas at ambient temperatures without refrigeration and at pressures ranging from 1500 to about 3000 psi.
In U.S. Pat. No. 4,139,019 an arrangement is described for loading natural gas into the movable pressure vessels, and usually includes an oil-gas separator unit and a dehydrator unit connected between the gas well and the loading equipment to properly condition the natural gas for transport. The loading equipment itself as described in the patent includes a loading manifold connected to receive natural gas for transport, at least one loading conduit connected with the loading manifold and having a flow-control valve therein, and a flexible conduit connected at one end to the loading conduit and equipped at its other end with a coupler portion designed to mate with a corresponding coupler portion carried on the movable pressure vessel. Usually, two loading conduits are connected to the loading manifold, so that two separate movable pressure vessels can be connected to the loading manifold at the same time. When the filling of one of the pressure vessels is completed, its associated flow-control valve is closed and the flow-control valve for the other pressure vessel is then opened to commence filling the latter.
The present inventors made improvements on the basic method and system of U.S. Pat. No. 4,139,019, and obtained U.S. Pat. No. 4,213,476 on those improvements. In the latter patent an improved method and system is described for producing and transporting natural gas, which again utilizes movable pressure vessels to transport natural gas at ambient temperatures and under a pressure that is preferably in the 2,000 to 3,000 psi range. The arrangement for loading natural gas into the movable pressure vessels is similar in the two patents, but U.S. Pat. No. 4,213,476 includes the added feature of providing a means to effect automatic switchover from a filled to an empty pressure vessel, with no interruption in natural gas flow. This feature assures continuous production of the gas well even if an operator is not present to effect a switchover manually.
The inventions which are the subject of these two patents have proved successful in practice, and have made it possible to recover natural gas from isolated gas wells. However, it has been found that the natural gas loading equipment as described in the two patents, while satisfactory in many situations, has some disadvantages. For example, the loading manifold and loading conduit arrangements shown in the patents normally require considerable construction at the well head, which can sometimes be expensive relative to the natural gas produced. In addition, the flexible hoses utilized to connect the loading conduits with the pressure vessels are subject to intensive wear because of the high pressures utilized, and need to be replaced rather frequently. Further, the flexible hoses can pose safety problems in handling and use, under certain circumstances.
There is need for an improved natural gas loading station for use in most efficiently practicing the natural gas production and transporting methods set forth in the two noted United States patents, one which is portable so that it can be moved from site to site, and which includes features to assure the maximum handling safety for the natural gas. The present invention is intended to meet that need.